Pulp stock flow control



Nov. 5, 1946. J. A. RosMArr lPULP s'rocx FLOW CONTROL 2 sheets-sheet 1 Filed Oct. 2L 1944 .L A. RosMArr I y 2,410,526

Nov. 5, 1946.

` l PULP, STOCK FLow CONTROL Filed Oct. 2, 1944 2 Sheets-*Sheet 2 l aa FI .4 ,20 as 4 f V mm mum( Aai E 2,410,526 PULP s'rocu rLoW coN'raoL .lohn A. Rosmait, Appleton, Wis., assgnor to D. J.

Murray Manufacturing Co., Wausau, Wis., va l corporation of Wisconsin Application Gctolier 2, 1944i, Serial No. 556,796

il Claims.

. l. This invention relates generally to improvements in the` 'art 0f paper making, and relates (ci. ca -ic) more particularly to improvements in the construction and operation of mechanism for collecting, spreading and controlling the flow of effluent or pulp stock as it is discharged from the screens to the head boxes of paper manufacturing machines especially of theF-ourdrinier type.

The primary object of my present invention is to provide an improved mode of collecting, distributing and controlling the flow of efuent stock as it passes from the screens to the head box of a Fourdriner type of paper making machine or the like.

The consistency of efduent or pulp stock delivered from the screens toward the Fourdrinier wire of Well known paper making machinery, is relatively low, that is, it has practically the fluidity of Water and contains only from one-tenth to three-tenths of solid matter such as bres, in suspension. Depending of course upon the socalled freeness or slowness of the stock, even at these low consistencies there is a denite tendency for the fibres to settle or ilocculate into small bundles, thus producing lumpy and extremely undesirable formations. This condition is aggravated by aeration, turbulency, crossiows, etc. as the fibre stock passes from the surge box and through the customary pipe headers, Ts and elbows connecting the surge box with the iirst pass of the head box. The use of this prior. type of conductors results in the production of' numerous sharp turns, corners, and quiescent zones in which eddy currents and badly settled areas are constantly formed, thus causing sliml7 pulp formations to momentarily lodge and to subsequently break loose and to create lumps, holes, and spots in the nal paper. This prior type of header piping also results in considerable lossin velocity head due to the sharp entrance of the stock and the subsequent multiple bends, and requires the screens to be located at elevations suiiciently high to compensate for these hydraulic losses and to properly deliver the euent stock into the first pass of the'head box against the relatively high static head existing therein. and this static head must constantly be maintained sufficient to accomodate the highest speeds at which the machinery is operable.

In these prior paper making systems, the last connection of the piping header usually terminates in three or moreoutlets, depending .upon

y the width of the Fourdrinier wire; and these outlets are slots or holes cut into the rear wall of the head bon and are to mscharge the iluent stock at laterally spaced intervals into the lower portion of the rst pass of the head box, which pass is ordinarily a relatively deep rectangular space having an upper outlet communicating'vvith the second pass. The violent injection of the fibre bearing stock through these several outlets and the drastic change in direction of iiow produced thereby, further reduces the velocity of ilow Within the head box and interferes with uniformity in paper production. Then too, at the higher speeds of these paper making machines, the level of the liquid in the head box between the first and last passes, is not nearly as high as during low speed operation, but at high speeds the level in the head box as a whole should be at a. maximum'. The relative elevation of the screens with respect to the Fourdrinier wire, is therefore dependent upon the maximum speed of themachin'e, and the elevation of the screen outlets must be sucient to insure proper capacity of flow through the piping headers and head box and to constantly overcome al1 hydraulic losses. lf, therefore, hydraulic losses are encountered due to the use of inecient conduits between the screen and head box, raising of the screens in an eiort to obviate such losses, augments the undesirable condition Whenever the apparatus is operating at low speeds at which the levels in the head box are far below the top, andl only a fraction of the high speed levels is needed above the wire deck for the production of heavier weight paper. Under such operating conditions when utilizing lesser flow capacities and somewhat; higher pulp consistency in the prior circuitous conduits together with high" screen elevations, cascading resultsand makes it practically impossible to produce sheets of paper of proper texture and thickness.

It is therefore a more specific object of the present invention to provide an improved system of stock iiow kcontrol from the screens to the wires of a Fourdrinier type" of paper making machines,

which eliminates all of the above mentioned dile culties, and which enables elicient production of paper of desired thickness and substantial uniformity and any desired practiced speeds.

Another specic object of this .invention is to provide improved apparatus for controlling the flow of eilluent stock from a. surge box or the like to the ilrst passA of the head box of a paper making machine, embodying a minimumy number oi turns or changes in direction of flow, and of such formation that hydraulic losses are minimized and excessively high screen elevations are made unnecessary.

such as shown in ananas lA further specific object ofthe invention is to provide an improved conduit assemblage for conducting bre pulp stock from the screens to the head box of a paper producing machine, wherein the velocity of iow of the liquid delivered from 'the surge tank is gradually decelerated and converted into pressure energy sufllcient to eil'ectively overcome thestatic pressure head in the first pass of the head box under all conditions of operation.

Still another specific object of my invention is to provide improved mechanism` for eiecting uniform delivery of the eluent pulp stock into the .first pass of the head box of a paper making machine, throughout the entire width of the box and in parallel directions, and for regulating or controlling the now into' the head box so as to produce smooth entry andv to avoid undesirable turbulency and agitation.

An additional specific object of this invention is to provide improved instrumcntali-ties for conducting the stream of pulp stock through a paper making machine, in a manner which will avoid eddy currents while aiding in deaeration ofthe eiliuent stock and causing the liquid to flow in a solid and smooth stream throughout its course. Another specic object of the invention is to provide a simple and compact flow distributing and control unit which may be used either singly or in multiple and applied to either existing or new paper making installations at moderate cost, so as to insure proper now under varying conditions of operation, and which is also highly exible in its adaptations and efficient in normal operation.

While the invention has been shown and described herein as being especially adapted for use in connection 'with Fourdrinier paper making machines of variable capacity and characteristics, it is not my desire or intention to unnecessarily restrict the scope or utility of the improved feav inlet I9 which normally receives the pulp stock These and vother specic objects and advantages of my invention will be apparent from the following detailed description.

A clear conception of the features constituting the present improvement, and of the construction and operation of several typesof my improved ow control mechanism, may be had byreferring to the drawings accompanying and forming a part of this specication wherein like reference characters designate the saine or similar parts in the various views.

Fig. 1 is a diagram or now sheet illustrating circle concentric with the tube axis.

a typical Fourdrinier type of paper making installaton showing the general location of my im- 'proved apparatus;

Fig. 2 is a somewhat enlarged part sectional side elevation of the improved flow control uni-t showing the same associated with the screen outlet, surge box and head box the latter being shown in section;

Fig. 3 is a rear view of the assemblage shown in Fig. 2, embodying a single improved dow control unit;

Fig. 4 is a further enlarged central vertical Y section through a type of the improved flow control unit having a ow decelerating tube which is of circular cross-section throughout its length;

Fig.` 5 is a. top view of a single now control unit Fig. 4;

Fig. 6 is a still further enlarged vertical section vthrough one of the dow regulating gates of my improved control assemblages;

Fig. 7 is a part sectional top view of another type of the improved flow decelerating tube, having circular cross-section at the top and elliptical cross-section at the enlarged bottom portion thereof; and

Fig. 8 is a somewhat diagrammatic top view of a multiple installation of my improved ow control unit.

I I from a multiple pass head box 20 of usual con-v struction; and one orv more now decelerating tubes 2l, now spreaders 22, and flow control gates 23 of improved structure interposed between the surge box- I5 and the lower rear inlet end of the head box 20.A

The improved iiow control assemblages embodying my present invention and which are adapted to be interposed between the surge box I5 and the head box 2U, may be constructed as units of any desired capacity adapted to be utilized either singly or in multipledepending upon the width of the Fourdrinier wire I5, and

the decelerating tubes used in these improved asv clusive, the ow deceleratng tube 2I of each unit,

comprises a frustro-conical upright sheet metal tube having circular cross-section throughout its length but beingof gradually enlarged diameter from its upper inlet to its lower outlet. Each frustro-conical tube is provided with a series of four internal radial vanes 24 the inner edges of which are parallel and terminate in a common The upper smaller inlet end of each decelerating tube 2I is in direct and open communication with the lower outlet 25 of the surge box I5, and the lower enlarged outlet end of the tapered tube 2| is provided with a cylindrical apron 26 which is in open communication with the adjacent spreader 22;

As particularly illustrated in Figs. '7 and 8,' the slightly modied flow decelerating tube 2|' of each unit, comprises an upright sheet-metal tube having gradually downwardly expanding crosssectional area of circular cross-section at its smaller top or inlet end and of elliptical crosssection at its enlarged bottom or outlet end. This modified tube 2l is also provided with a. series of four internal radial vanes the inner edges of cross-section with the major axis of the ellipse lying in a plane extending across the end of the head box 20 and transversely of the direction of now through this box.

The improved iiow spreaders 22 are adapted to cooperate with either type of ydecelerating tube 2I, 2|', and each of these spreaders 22 comprises a sheet metal casing which is laterally widened or spread out to the full width of a small standard head box 20 as in Figs. 3( and 5, or to one-half the width ot a larger head box 20 as in Fig. 8, or to one-third of a still larger box in installations of still greater capacity. The width of the spreaders 22 may be standard in the individual flow control units, and each spreader casing has an inclined bottom 21 directly beneath the apron 28, 28' of the adjacent central decelerating tube 2|, 2|', and also has a front lower outlet slot 28 communicating with the extreme lower rear end of the ilrst pass 29 of the adjacent head box 20. Diagonal partitions 30 which radiate from the central axis of the corresponding decelerating tube and which divide the slot 28 into three parts of equal length, are also provided within each spreader 22, and these partitions may be either plane as in Fig. 5 or curved slightly away from the central planeof the spreader as in Fig. 8.

-As indicated in Figs. 2, 4, 5 and 6, my improved ilow regulating gates 23, are ilexible elongated elements swingably suspended from spreader nozzles 3| which are in open communication with the spreader slots 28. As shown, there are three independent gates 23 associated with each spreader 22, and each. gate is secured to the adjacent nozzle 3| by means of a curvedplate 32 and cap screws 33, and is adapted to be swungl from one dot-and-dash line position to another as illustrated in Fig. 6, by Vmeans of an independently adjustable actuating rod 34, all of which extend upwardly through the ilrst pass 29 of the head box 20. The lower end of each adjusting rod 36 extends through a slot formed in a tubular bead 36 formed at the outer swinging end-of the adjacent gate 23, and is provided with an integral transverse bar 31 snugly engaging the corresponding bead 36. The upper end of each adjusting rod 3d is screw threaded and coacts with a hand wheel 38 having a hub 39-journalled for rotation in a bracket 40, and each rod 34 is also provided with upper and lower stop collarslll l, 42' for limiting the opening and closing ,of the gates 23, see

Fig. 4. 'I'he swinging gates 23 cooperate with the bottom of the head box 20 to provide sniooth transition slots leading into the rst pass i9, and these gates may be independently adjusted so as to provide for diierent delivery openings at different portions of the slots 28 and nozzles 3|. v

As previously indicated, the improved ilow decelerating spreader and regulating units may be utilized either singly as in Figs. 3 and 5, or in multiple as in Fig. 8, and their use in multiple is not necessarily limited to two units. These units may also be applied either to new installations or to existing installations having Fourdrinier wires I6 of standard widths, thus facilitating manufacture of the units in large lots and application thereof to the paper making machines. Since the normal functioning of the circular and elliptical sectioned tubes 2|, 2|' is substantially the same, it will suice to describe the normal operation of only one of these alternative structures.

During normal operation of the improved iiow control units, the screens I0 will be receiving an abundant supply of pulp stock from the ow box l2 past the fan pump I3, and after treating the eilluent stock, the screens deposit the material into the surge box i5. From the surge box i5, the lbrous pulp ii flows through the youtlet opening 25, into the decelerating tube 2| wherein the velocity of iiow is gradually decelerated due to the gradually increasing cross-sectional area, while excessive swirling or whirling oi the stream is prevented by the radial 'vanos 2c. Following this initial deceleration of .the advancing pulp, the direction of ilow ls gradually changed from vertical to approximately hori- 'turbulency and aids v 22 andthe stream is further decelerated, spread and widened out to the full widthof the outlet slot 28, by the rear. top and bottom walls o! the spreader casing'. The partitions 30 within the spreader 22 also function to prevent eddies in the advancing spreading stream and to divide Athe same into segregated adjoining parts flowing through the slot 28 in substantially parallel directions. As the effluent stock flows through the nozzles 3| and past the gates 23 it enters the, lower portion of the irst pass of the head box 20 at relativelyy high velocity but without turbulency or excessive agitation, and under pressure suicient to overcome the static head of the liquid within the pass 29. The individual gates 23 may be readily adjusted with the aid of their manipulating rods 34 and handwheels 38 so as to insure smooth entry of the liquid' stock into the head box 20 throughout the entire width thereof, and the entering eilluent stock subsequently flows through the successive passes 'of the head box and is leventually deposited upon the Fourdrinier wire I6 through the inlet I9. In this manner the im'- proved ilow control mechanism gradually conducts the bre stock from the surge box |5 to the head box 20 with but a single gradual change in direction of flow, while simultaneously converting the velocity of ilow into pressure energy suiiclent to overcome thgstatic head and also avoiding turbulency and eddies. From the foregoing detailed description of the construction and operation of my improved pulp stock flow control system, it should be apparent that the invention provides control mechanism whichbesides being simple and compact in construction, is also highly eillcient in operation and functions automatically after the gates 23 have been set to meet desired operating conditions. The improvement may obviously be embodied in units of predetermined capacity adapted to be used either singly or in multiple, and each unit is capable of eiectively collecting, decelerating,

distributing and controlling the flow of liquid therethrough, and is devoid of multiple bends, corners, and quiescent zones in which bres are apt to fiocculate or gather. While the circular decelerating tube 2| and apron 26 may perhaps be more readily constructed and applied to the spreader 22, the elllptic'al or oval type of tube 2|' and apron 28 facilitates lateral vspreading and distribution of the eilluent stock, and both types of'tubes as well as the spreaders 22 may be readily constructed of sheet metal and at exceedingly moderate oost. The use of the baies 24 in the decelerating tubes and of the partitions 30 in the spreaders 22, eliminates swirling and in proper distribution of the stock, and the independently manipulable gates 23 enable. the operator lto readily and eectively control the iiow so as to insure uniform distribution throughout the entire width of the head box 20. It-is also noteworthy that with my improved assemblage, the single change in direction. of flow of each stream. is accomplished at the point of maximum cross-sectional area' and minimum velocity thereof and just prior to final distribution and injection of the liquid into the head box, 'thus permitting most emcient and smooth spreading of the eiluent stock without creating undesirable disturbances. The depend-- ing aprons at the lowervends of the expanding decelerating tubes, also enhance the nal spread-A ing and distribution, and-the gates 23 may be readily formed of exible sheet material and are herein shown and described, for various modiii'4 cations within the scope of the appended claims may occur to persons skilled in the art.

I claim: V

l. In combination with the surge andA head boxes oi a paper making machine, means for initially decelerating the ilow of efiiuent stock discharged from the surge box and for converting its Velocity energy -into pressure, means for spreading the stock while under considerable pressure and as it ows away from said decelerating means, means for directly delivering the spread stock under pressure into the lower portion of `the rst pass of the head box'throughout the entire width of the latter, and means for locally varying the cross-sectional area of said delivery means to insure uniform distribution of the stock. v

2. In combination with the surge and he'ad boxes of a paper making machine, means for initially decelerating the flow of eilluent stock discharged fr`om the surge-box and for converting fil velocity energy thereof into pressure, means for preventing swirling of the stock as it passes through said decelerating means, means for laterally spreading the stream of stock flowing out of said de'celerating means and for, further converting velocity energy thereof into pressure, and means for directly delivering the Ispread stock under considerable pressure intothe lower pori;

tion of the first pass of the head box.

3. In combination with the surge and head` pressure, and nozzles for delivering the spread stream under pressure created by said tube and spreader into the lower end of the iirst pass of the head box.

5. A decelerating and ilow control unit insertible between the surge and head boxes of 'a paper making machine, said unit comprising, a

. downwardly enlarging tapered tube for initially decelerating the flow of efiluent stock discharged into the tube from the surge box and for converting velocity energy thereof into pressure, a spreader in open communication directly with the outlet end of said tube for changing the dlrection of flow of the initially decelerated stream and for spreading it laterally, partitions within said spreader for dividing the stream into segregated parallel ilow sections, and nozzles for -delivering thespread stream under pressure created by said tube into the lower end of the rst pass of the head box.

6. A decelerating and iiow control unit insertible between the surge and head boxes of a paper making machine, said unit comprising, a downwardly enlarging tapered tube for initially decelerating the flow of efuent stock discharged into the tube from the surge box and for converting velocity energy thereof into pressure, a spreader in open communication directly with the outlet end of said tube -for changing the direction of now of the initially decelerated stream and for spreading it laterally, nozzles for delivering the spread stream under pressure created by said tube into the lower end of the iirst pass 'of the head box, and independently adjustable gates for controlling the ow through said nozzles.

7. A decelerating and flow control assemblage for paper making machineshaving surge and head boxes, said assemblage comprising, a downwardly expanding upright tube having itssmaller upper linlet enddirectly communicable with the A surge box, said tube having circular transverse boxes of a paper making machine. means tor-'1'1- discharged from the surge box and for converting velocity energy thereof into pressure` means f for preventing swirling of the stock as it passes through said decelerating means, means for laterally spreading the stream of stock owlng out of said decelerating means and for further con-` verting velocity energy thereof into pressure,

velocity energy thereof into pressure, varies inv said tube for preventing whirling of the liquid nowing therethrough, a spreader in open communication with the outlet end of said tube for changing the direction of ilow of the 'initially decelerated stream and for spreading it laterally to further convert velocity energy thereof into `cross-section at its `upper inlet end and oval transverse cross-section at its lower outlet end, a .spreader in open communication with the -large'r'lower outlet end of said tube and having a initially decelerating the new of eilluent stock fbottomidsposed nvertica'l aunement With the tubeltor changingthe flow from vertical to ap- .proximately hori zontal, and independently adl iusizable. means," ior regulating the delivery of eiiluent stock from said spreader into the lower portion` of the head box at various localities l ,meansv within said'spreading means for Segre-5 fun-1' paper making machines having surge and gating the stock into a plurality of .parallelstreams, and means for directly deliveringthe spread stock under considerable pressure into the lower portion of the first pass of the head box'.

head boxes, said assemblage comprising, a down- ;wardly expanding upright tube having its smaller upper inlet end directly communicable with the surge box, a spreader in open communication with the larger lower outlet end of said tube and having a bottom disposed in vertical alinement with the tube for changing the flow from vertical to approximately horizontal, means within said spreader for dividing the flow therein into segregated parallel streams flowing toward the head box, and lindependently adjustable means for controllably admitting said streams under pressure to' the head box through the several divisionsand throughout substantially the entire width of the box. JOHN A. ROSMAIT. 

